#include <machine/asm.h>

/* LINTSTUB: Func: void *memcpy(void *dst, const void *src, size_t len) */
ENTRY(memcpy)
	/* save leaf functions having to store this away */
	push	{r0, lr}		/* memcpy() returns dest addr */

	subs	r2, r2, #4
	blt	.Lmemcpy_l4		/* less than 4 bytes */
	ands	r12, r0, #3
	bne	.Lmemcpy_destul		/* oh unaligned destination addr */
	ands	r12, r1, #3
	bne	.Lmemcpy_srcul		/* oh unaligned source addr */

.Lmemcpy_t8:
	/* We have aligned source and destination */
	subs	r2, r2, #8
	blt	.Lmemcpy_l12		/* less than 12 bytes (4 from above) */
	subs	r2, r2, #0x14
	blt	.Lmemcpy_l32		/* less than 32 bytes (12 from above) */
	push	{r4}		/* borrow r4 */

	/* blat 32 bytes at a time */
	/* XXX for really big copies perhaps we should use more registers */
.Lmemcpy_loop32:
	ldmia	r1!, {r3, r4, r12, lr}
	stmia	r0!, {r3, r4, r12, lr}
	ldmia	r1!, {r3, r4, r12, lr}
	stmia	r0!, {r3, r4, r12, lr}
	subs	r2, r2, #0x20
	bge	.Lmemcpy_loop32

	cmn	r2, #0x10
	ldmiage	r1!, {r3, r4, r12, lr}	/* blat a remaining 16 bytes */
	stmiage	r0!, {r3, r4, r12, lr}
	subge	r2, r2, #0x10
	pop	{r4}		/* return r4 */

.Lmemcpy_l32:
	adds	r2, r2, #0x14

	/* blat 12 bytes at a time */
.Lmemcpy_loop12:
	ldmiage	r1!, {r3, r12, lr}
	stmiage	r0!, {r3, r12, lr}
	subsge	r2, r2, #0x0c
	bge	.Lmemcpy_loop12

.Lmemcpy_l12:
	adds	r2, r2, #8
	blt	.Lmemcpy_l4

	subs	r2, r2, #4
	ldrlt	r3, [r1], #4
	strlt	r3, [r0], #4
	ldmiage	r1!, {r3, r12}
	stmiage	r0!, {r3, r12}
	subge	r2, r2, #4

.Lmemcpy_l4:
	/* less than 4 bytes to go */
	adds	r2, r2, #4
#ifdef __APCS_26_
	ldmiaeq sp!, {r0, pc}^		/* done */
#else
	popeq	{r0, pc}		/* done */
#endif
	/* copy the crud byte at a time */
	cmp	r2, #2
	ldrb	r3, [r1], #1
	strb	r3, [r0], #1
	ldrbge	r3, [r1], #1
	strbge	r3, [r0], #1
	ldrbgt	r3, [r1], #1
	strbgt	r3, [r0], #1
	pop	{r0, pc}

	/* erg - unaligned destination */
.Lmemcpy_destul:
	rsb	r12, r12, #4
	cmp	r12, #2

	/* align destination with byte copies */
	ldrb	r3, [r1], #1
	strb	r3, [r0], #1
	ldrbge	r3, [r1], #1
	strbge	r3, [r0], #1
	ldrbgt	r3, [r1], #1
	strbgt	r3, [r0], #1
	subs	r2, r2, r12
	blt	.Lmemcpy_l4		/* less the 4 bytes */

	ands	r12, r1, #3
	beq	.Lmemcpy_t8		/* we have an aligned source */

	/* erg - unaligned source */
	/* This is where it gets nasty ... */
.Lmemcpy_srcul:
	bic	r1, r1, #3
	ldr	lr, [r1], #4
	cmp	r12, #2
	bgt	.Lmemcpy_srcul3
	beq	.Lmemcpy_srcul2
	cmp	r2, #0x0c
	blt	.Lmemcpy_srcul1loop4
	sub	r2, r2, #0x0c
	push	{r4, r5}

.Lmemcpy_srcul1loop16:
#ifdef __ARMEB__
	mov	r3, lr, lsl #8
#else
	mov	r3, lr, lsr #8
#endif
	ldmia	r1!, {r4, r5, r12, lr}
#ifdef __ARMEB__
	orr	r3, r3, r4, lsr #24
	mov	r4, r4, lsl #8
	orr	r4, r4, r5, lsr #24
	mov	r5, r5, lsl #8
	orr	r5, r5, r12, lsr #24
	mov	r12, r12, lsl #8
	orr	r12, r12, lr, lsr #24
#else
	orr	r3, r3, r4, lsl #24
	mov	r4, r4, lsr #8
	orr	r4, r4, r5, lsl #24
	mov	r5, r5, lsr #8
	orr	r5, r5, r12, lsl #24
	mov	r12, r12, lsr #8
	orr	r12, r12, lr, lsl #24
#endif
	stmia	r0!, {r3-r5, r12}
	subs	r2, r2, #0x10
	bge	.Lmemcpy_srcul1loop16
	pop	{r4, r5}
	adds	r2, r2, #0x0c
	blt	.Lmemcpy_srcul1l4

.Lmemcpy_srcul1loop4:
#ifdef __ARMEB__
	mov	r12, lr, lsl #8
#else
	mov	r12, lr, lsr #8
#endif
	ldr	lr, [r1], #4
#ifdef __ARMEB__
	orr	r12, r12, lr, lsr #24
#else
	orr	r12, r12, lr, lsl #24
#endif
	str	r12, [r0], #4
	subs	r2, r2, #4
	bge	.Lmemcpy_srcul1loop4

.Lmemcpy_srcul1l4:
	sub	r1, r1, #3
	b	.Lmemcpy_l4

.Lmemcpy_srcul2:
	cmp	r2, #0x0c
	blt	.Lmemcpy_srcul2loop4
	sub	r2, r2, #0x0c
	push	{r4, r5}

.Lmemcpy_srcul2loop16:
#ifdef __ARMEB__
	mov	r3, lr, lsl #16
#else
	mov	r3, lr, lsr #16
#endif
	ldmia	r1!, {r4, r5, r12, lr}
#ifdef __ARMEB__
	orr	r3, r3, r4, lsr #16
	mov	r4, r4, lsl #16
	orr	r4, r4, r5, lsr #16
	mov	r5, r5, lsl #16
	orr	r5, r5, r12, lsr #16
	mov	r12, r12, lsl #16
	orr	r12, r12, lr, lsr #16
#else
	orr	r3, r3, r4, lsl #16
	mov	r4, r4, lsr #16
	orr	r4, r4, r5, lsl #16
	mov	r5, r5, lsr #16
	orr	r5, r5, r12, lsl #16
	mov	r12, r12, lsr #16
	orr	r12, r12, lr, lsl #16
#endif
	stmia	r0!, {r3-r5, r12}
	subs	r2, r2, #0x10
	bge	.Lmemcpy_srcul2loop16
	pop	{r4, r5}
	adds	r2, r2, #0x0c
	blt	.Lmemcpy_srcul2l4

.Lmemcpy_srcul2loop4:
#ifdef __ARMEB__
	mov	r12, lr, lsl #16
#else
	mov	r12, lr, lsr #16
#endif
	ldr	lr, [r1], #4
#ifdef __ARMEB__
	orr	r12, r12, lr, lsr #16
#else
	orr	r12, r12, lr, lsl #16
#endif
	str	r12, [r0], #4
	subs	r2, r2, #4
	bge	.Lmemcpy_srcul2loop4

.Lmemcpy_srcul2l4:
	sub	r1, r1, #2
	b	.Lmemcpy_l4

.Lmemcpy_srcul3:
	cmp	r2, #0x0c
	blt	.Lmemcpy_srcul3loop4
	sub	r2, r2, #0x0c
	push	{r4, r5}

.Lmemcpy_srcul3loop16:
#ifdef __ARMEB__
	mov	r3, lr, lsl #24
#else
	mov	r3, lr, lsr #24
#endif
	ldmia	r1!, {r4, r5, r12, lr}
#ifdef __ARMEB__
	orr	r3, r3, r4, lsr #8
	mov	r4, r4, lsl #24
	orr	r4, r4, r5, lsr #8
	mov	r5, r5, lsl #24
	orr	r5, r5, r12, lsr #8
	mov	r12, r12, lsl #24
	orr	r12, r12, lr, lsr #8
#else
	orr	r3, r3, r4, lsl #8
	mov	r4, r4, lsr #24
	orr	r4, r4, r5, lsl #8
	mov	r5, r5, lsr #24
	orr	r5, r5, r12, lsl #8
	mov	r12, r12, lsr #24
	orr	r12, r12, lr, lsl #8
#endif
	stmia	r0!, {r3-r5, r12}
	subs	r2, r2, #0x10
	bge	.Lmemcpy_srcul3loop16
	pop	{r4, r5}
	adds	r2, r2, #0x0c
	blt	.Lmemcpy_srcul3l4

.Lmemcpy_srcul3loop4:
#ifdef __ARMEB__
	mov	r12, lr, lsl #24
#else
	mov	r12, lr, lsr #24
#endif
	ldr	lr, [r1], #4
#ifdef __ARMEB__
	orr	r12, r12, lr, lsr #8
#else
	orr	r12, r12, lr, lsl #8
#endif
	str	r12, [r0], #4
	subs	r2, r2, #4
	bge	.Lmemcpy_srcul3loop4

.Lmemcpy_srcul3l4:
	sub	r1, r1, #1
	b	.Lmemcpy_l4
END(memcpy)
